1. Field of Disclosure
The present disclosure relates generally to the cooling systems used in a data center environment, and more particularly to a cooling rack fan module and related methods of cooling the data center.
2. Discussion of Related Art
Equipment enclosures or racks for housing electronic equipment, such as data processing, networking and telecommunications equipment have been used for many years. Such racks are used to contain and to arrange the equipment in large data centers, as well as small wiring closets and equipment rooms. In certain embodiments, an equipment rack can be an open configuration and can be housed within a rack enclosure, although the enclosure may be included when referring to a rack. A standard rack typically includes front mounting rails to which multiple units of electronic equipment, such as servers, CPUs and telecommunication equipment, are mounted and stacked vertically within the rack. With the proliferation of the Internet, it is not uncommon for a data center to contain hundreds of these racks. Further, with the ever decreasing size of computer equipment, and in particular, computer servers and blades, the number of electrical devices mounted in each rack has been increasing, raising concerns about adequately cooling the equipment.
Heat produced by rack-mounted equipment can have adverse effects on the performance, reliability and useful life of the equipment components. In particular, rack-mounted equipment, housed within an enclosure, may be vulnerable to heat build-up and hot spots produced within the confines of the enclosure during operation. The amount of heat generated by a rack of equipment is dependent on the amount of electrical power drawn by equipment in the rack during operation. In addition, users of electronic equipment may add, remove, and rearrange rack-mounted components as their needs change and new needs develop.
Previously, in certain configurations, data centers have been cooled by computer room air conditioner (“CRAC”) units that are positioned around the periphery of the data center room. These CRAC units intake air from the fronts of the units and output cooler air upwardly toward the ceiling of the data center room. In other embodiments, the CRAC units intake air from near the ceiling of the data center room and discharge cooler air under a raised floor for delivery to the fronts of the equipment racks. In general, such CRAC units intake room temperature air (at about 72° F.) and discharge cold air (at about 55° F.), which is blown into the data center room and mixed with the room temperature air at or near the equipment racks. The rack-mounted equipment typically cools itself by drawing air along a front side or air inlet side of a rack, drawing the air through its components, and subsequently exhausting the air from a rear or vent side of the rack.
Examples of cooling units that may be configured to be placed within a data center may be made to: U.S. patent application Ser. No. 11/335,874, entitled COOLING SYSTEM AND METHOD, by Neil Rasmussen, John Bean, Greg Uhrhan and Scott Buell, filed on Jan. 19, 2006; U.S. Pat. No. 7,365,973, entitled COOLING SYSTEM AND METHOD, by Neil Rasmussen, John H. Bean, Greg R. Uhrhan and Scott D. Buell, issued on Apr. 29, 2008; and U.S. patent application Ser. No. 11/335,901, entitled COOLING SYSTEM AND METHOD, by Neil Rasmussen, John Bean, Vincent Long, Greg Uhrhan and Matthew Brown, filed on Jan. 19, 2006, all of which are incorporated herein by reference in their entirety for all purposes. Other examples of cooling units may be found in U.S. patent application Ser. No. 11/504,382, entitled METHOD AND APPARATUS FOR COOLING, by Ozan Tutunoglu, filed on Aug. 15, 2006, abandoned, and U.S. patent application Ser. No. 11/504,370, entitled METHOD AND APPARATUS FOR COOLING, by Ozan Tutunoglu and David Lingrey, filed on Aug. 15, 2006, 2006, both of which are incorporated herein by reference in their entirety for all purposes.
There is a continuous need to improve the performance of the cooling unit, including increasing energy efficiency and air flow rate. FIG. 1 illustrates a prior art cooling unit 10. One issue associated with such cooling units is that they are noisy. FIG. 2 illustrates a prior art fan module 20 having a fan bezel 22, a fan assembly 24, and a finger guard 26. When all eight fan modules 20 of the cooling unit 10 are operating at maximum fan speed, the noise may reach 90 decibels (dB) in front of cooling unit, at a distance of one meter from the cooling unit.
Other equipment having fans that are used within the data center, such as ventilation fans, is also noisy. To meet high air flow requirement, the fan speeds of the fans may reach 6500 revolutions per minute (RPM). When all of the fan modules within a particular cooling unit are running at maximum speed, the sound level is too high. Reducing the noise level presents several challenges. One challenge is that a cooling unit having a 300 mm width is too small to use traditional sound attenuation solution, such as a static pressure chamber and/or sound isolation. Another challenge is that the air flow requirement is very high, and any sound solution must balance the air flow reduction and sound attenuation effects.